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EP-4736544-A1 - NETWORK DTX/DRX WITH RESPECT TO UE IN NON-CONNECTED STATE

EP4736544A1EP 4736544 A1EP4736544 A1EP 4736544A1EP-4736544-A1

Abstract

Systems and methods related to Discontinuous Transmission (DTX) and/or Discontinuous Reception (DRX) with respect to a User Equipment(s) (UE(s)) in a non-connected state are disclosed. In one embodiment, a method performed by a network node of a Radio Access Network (RAN) of a cellular communications system comprises transmitting one or more reference signals needed by User Equipments (UEs) in non-connected state, during at least one of a plurality of network discontinuous transmission, DTX, windows, and refraining from transmitting the one or more reference signals needed by UEs in non-connected state, during time periods between the plurality network DTX windows. In this manner, longer (e.g., longer than, e.g., micro-sleep) sleep opportunities and network DTX in network nodes may be enabled, e.g., to reduce network energy consumption. Embodiments of a UE and methods of operation thereof are also disclosed.

Inventors

  • HÖGLUND, Andreas
  • LIBERG, OLOF
  • PARKVALL, STEFAN
  • WANG, YI-PIN ERIC
  • NADER, ALI
  • BERGMAN, JOHAN
  • THANGARASA, Santhan

Assignees

  • Telefonaktiebolaget LM Ericsson (publ)

Dates

Publication Date
20260506
Application Date
20240628

Claims (20)

  1. 1. A method performed by a network node of a Radio Access Network, RAN, of a cellular communications system, the method comprising: transmitting (310) one or more reference signals needed by User Equipments, UEs, in nonconnected state, during at least one of a plurality of network discontinuous transmission, DTX, windows; and refraining (312) from transmitting the one or more reference signals needed by UEs in nonconnected state, during time periods between the plurality network DTX windows.
  2. 2. The method of claim 1, wherein transmitting (310) the one or more reference signals comprises, for a network DTX window from among the at least one of the plurality of network DTX windows, transmitting (310) the one or more reference signals such that transmission of the one or more reference signals starts a defined or configured amount of time before a start of the network DTX window.
  3. 3. The method of claim 1 or 2, wherein transmitting (310) the one or more reference signals comprises, for a network DTX window from among the at least one of the plurality of network DTX windows, transmitting (310) the one or more reference signals such that transmission of the one or more reference signals ends a defined or configured amount of time after an end of the network DTX window.
  4. 4. The method of any of claims 1 to 3, wherein the plurality of network DTX windows are arranged in accordance with a predefined or configured network DTX window pattern.
  5. 5. The method of claim 4, wherein the predefined or configured network DTX window pattern comprises any one or more of: a start time, a network DTX window length, and a network DTX window periodicity.
  6. 6. The method of any of claims 1 to 5, wherein transmitting (310) the one or more reference signals comprises transmitting multiple instances of a same reference signal or multiple different reference signals in a same one or more symbols.
  7. 7. The method of any of claims 1 to 5, wherein transmitting (310) the one or more reference signals comprises transmitting multiple instances of a same reference signal or multiple different reference signals in a same one or more symbols via any one of or any combination of two or more of: time domain multiplexing, frequency domain multiplexing, and spatial domain multiplexing.
  8. 8. The method of any of claims 1 to 7, wherein the one or more reference signals needed by UEs in a non-connected state comprise any one or more of: a cell-specific reference signal, a synchronization signal block, a channel state information reference signal, and a tracking reference signal.
  9. 9. The method of any of claims 1 to 8, wherein transmitting (310) the one or more reference signals comprises transmitting a reference signal, needed by UEs in a non-connected state, that spans two or more consecutive symbols in the time domain, two or more physical resource blocks in the frequency domain, or both two or more consecutive symbols in the time domain and two or more physical resource blocks in the frequency domain.
  10. 10. The method of claim 9, wherein a number of consecutive symbols in the time domain spanned by the reference signal is configurable and/or a number of physical resource blocks in the frequency domain spanned by the reference signal is configurable.
  11. 11. The method of any of claims 1 to 10, wherein transmitting (310) the one or more reference signals comprises transmitting (310) at least one of the one or more reference signals over a bandwidth that exceeds a maximum receive bandwidth of at least one UE that is to receive the at least one of the one or more reference signals.
  12. 12. The method of any of claims 1 to 11, wherein transmitting (310) the one or more reference signals comprises repeating transmission of at least one of the one or more reference signals in the frequency domain in at least one time instance.
  13. 13. The method of any of claims 1 to 11, wherein transmitting (310) the one or more reference signals comprises frequency multiplexing two or more of the reference signals in a same time instance.
  14. 14. The method of any of claims 1 to 13, wherein the plurality of network DTX windows is one set of network DTX windows from two or more sets of network DTX windows.
  15. 15. The method of claim 14, wherein the two or more sets of network DTX windows comprises two or more different sets of network DTX windows for different coverage levels.
  16. 16. The method of any of claims 1 to 15, wherein the plurality of network DTX windows are coordinated with another radio access technology.
  17. 17. The method of any of claims 1 to 16, wherein the plurality of network DTX windows are coordinated among two or more cells that belong to a same core network tracking area and/or a same radio access network notification area.
  18. 18. The method of any of claims 1 to 17, further comprising deciding (302) to active network DTX operation based on one or more triggering criteria.
  19. 19. The method of claim 18, wherein transmitting (310) the one or more reference signals needed by UEs in non-connected state during at least one of a plurality of network DTX windows and refraining (312) from transmitting the one or more reference signals needed by UEs in nonconnected state during time periods between the plurality network DTX windows are performed in response to deciding (302) to active network DTX operation.
  20. 20. The method of claim 18 or 19, wherein the one or more triggering criteria comprise any one or any combination of two or more of the following: • network DTX operation is configured in the network node; • no UEs in a connected state in a respective cell; • no UE configured with persistent scheduling resources in a non-connected state; • no handover request received for time period Tl, where T1=N DRX cycles and N is a positive integer value that is greater than or equal to 1; and/or • no random access preambles received the network node for time period Tl, where T1=N DRX cycles where N is a positive integer value that is greater than or equal to 1.

Description

NETWORK DTX/DRX WITH RESPECT TO UE IN NON-CONNECTED STATE RELATED APPLICATIONS This application claims the benefit of provisional patent application serial number 63/510,813, filed June 28, 2023, the disclosure of which is hereby incorporated herein by reference in its entirety. TECHNICAL FIELD The present disclosure relates to a cellular communications network and, more specifically, to discontinuous transmission and/or discontinuous reception at a network node of a cellular communications network. BACKGROUND LTEIoT- 4G Internet of Things (loT) and massive Machine Type Communications (mMTC) use cases started to be addressed by the 3rd Generation Partnership Project (3GPP) in Release 13 and 4th Generation (4G) by several technologies: Long Term Evolution (LTE) for MTC (LTE-M) (Cat- Mi), Narrowband loT (NB-IoT), and Extended Coverage Global System for Mobile communications (EC-GSM). The mMTC use case is known as ‘Low Power Wide Area’ (LPWA) and focuses on simpler sensors and devices which should have ubiquitous coverage and long battery life. EC-GSM is an loT adaptation of the Global System for Mobile communications (GSM) standard, LTE-M is an loT adaptation of the LTE standard, whereas NB-IoT is more of a new radio access technology, but still specified in the LTE specifications. The loT adaptations for all three focused on improving the following: • Reduced device complexity (cost) • Reduced device energy consumption (longer battery life) • Improved coverage (e.g., to reach meters and sensors in basements) Commercially, NB-IoT and LTE-M have been more successful, network support has been rolled out globally, and enhancements have been specified in 3GPP in every release until Release 17. In addition, the lowest regular (Mobile Broadband, MBB) LTE UE categories, e.g., Cat-1, Cat-Ibis, and Cat-4, have been widely used for mid-range loT use cases (LTE-M, and especially NB-IoT, is more low-end). NRIoT- 5G 3GPP New Radio (NR) was introduced in Release 15 as 5th Generation (5G) technology. The least capable NR device in Release 15 was of relatively high complexity (cost) and therefore, in Release 17, Reduced Capability NR Devices (RedCap devices or RedCap User Equipments (UEs)) were introduced with mid-range use cases in mind (i.e., as a NR counterpart of LTE Cat-1 to Cat-4). In Release 18, further device complexity reductions are being specified (e.g., UE baseband bandwidth reduction and UE peak rate reduction). 6GI0T Firstly, there is an ongoing Radio Access Network (RAN) study item in Release 18 on ‘Ambient-IoT’, a device segment clearly below the lowest existing 3GPP device segment, which is NB-IoT. These devices are intended to be very small and cheap (e.g., small tags or stickers), but since the coverage may be considerably shorter than for existing solutions, it is not yet clear how they fit in to the 3GPP eco-system. For example, if this will be passive short-range solution introducing a new backscattering sidelink between UEs (smartphones) and Ambient-IoT devices (tags), or an active solution with relatively better coverage which can be integrated in existing network deployments. This is currently a study at RAN plenary level in Release 18, which will likely be followed up by subsequent studies in RAN working groups in Release 19. It is therefore still somewhat unclear if Ambient-IoT will be a 5G-Advanced technology or 6th Generation (6G) technology. Secondly, discussions have emerged on whether a new 6G native solution will be needed for LPWA use cases. The rationale being to address some shortcomings for NB-IoT and LTE-M which have now existed for some time. SUMMARY Systems and methods related to Discontinuous Transmission (DTX) and/or Discontinuous Reception (DRX) with respect to a User Equipment(s) (UE(s)) in a non-connected state are disclosed. In one embodiment, a method performed by a network node of a Radio Access Network (RAN) of a cellular communications system comprises transmitting one or more reference signals needed by User Equipments (UEs) in non-connected state, during at least one of a plurality of network discontinuous transmission, DTX, windows, and refraining from transmitting the one or more reference signals needed by UEs in non-connected state, during time periods between the plurality network DTX windows. In this manner, longer (e.g., longer than, e.g., micro-sleep) sleep opportunities and network DTX in network nodes may be enabled, e.g., to reduce network energy consumption. In one embodiment, transmitting the one or more reference signals comprises, for a network DTX window from among the at least one of the plurality of network DTX windows, transmitting the one or more reference signals such that transmission of the one or more reference signals starts a defined or configured amount of time before a start of the network DTX window. In one embodiment, transmitting the one or more reference signals comprises, for a network DTX window from among the at least one of the plura